Pressure-controlled electric switch for motor-operated pumps.



S. S. STAHL.

PRESSURE CONTROLLED ELECTRIC'SWITCH FOR MOTOR OPERATED PUMPS.

APPLICATION FILED APR.2I. 1914. 1,141,847. Patented June 1, 1915.

2 SHEETS-SHEET 1- WIT/V5885 TTOR/VEYS i s. s. STAHL. PRESSURE CONTROLLED ELECTRIC SWITCH FOR MOTOR OPERATED PUMPS.

APPLICATION FILED APILZII I914.

Patented June 1, 1915.

2 SHEETS-SHEET 2.

BY W

SIDNEY S. STLHL, OF CONNELLSVILLE, PENNSYLVANIA.

PRESSURE-CONTROLLED ELECTRIC SWITCH FOR MOTOR-OPERATED PUMPS.

Specification of Letters Patent.

Patented June 1, 1915.

Application filed April 21, 1914. Serial No. 833,529.

To all whom it may concern:

Be it known that I, SIDNEY S. STAHL, a citizen of the United States, and a resident of Gonnellsville, in the, county of Fayette and State of Pennsylvania, have invented a new and Improved Pressure-Controlled Electric Switch for Motor Operated Pumps, of which the following is a full, clear, and exact description.

This invention relates to an automatic switch of that type associated with a pressure responsive device for a pump or other system, whereby the switch of the pump driving motor is automatically opened and closed when the pressure of the fluid of the pump system increases or decreases to predetermined points.

The invention has for its general objects to improve and simplify the construction and operation of automatic switches of the character referred to so as to be reliable and efficient in use, comparatively inexpensive to manufacture and keep in operative condition, and so designed as to be extremely sensitive to fluid pressure variations.

Another object of the invention is the provision of an improved operating means for the switch. blade or blades, whereby the first part of either-the opening or closing movement is effected by fluid pressure variations, while the latter part of its movement is produced by an overbalancingweight which produces quick opening or closing of the switch.

With such objects) in view, and others which willappear as the description proceeds, the invention comprises various novel features of construction and arrangement of parts which will be set forth with particularity in the following description and claims appended hereto. 7 In the accompanying drawings, which illustrate one embodiment of the invention, and wherein similar characters of reference indicatecorresponding parts in all theviews, Figure 1 is a side view of a motor-operated pump with the pressure-controlled cut-out switch for the motor; Fig. 2 is a sectional view on the line 2-2, Fig. 3, drawn on a reduced scale; Fig. 3 is a side view of theswitch and its operating means; and Fig. 1 is a fragmentary side view of the switch operating means, showing the crank thereof in mid position.

Referring to the drawing, A designates a pump of the reciprocating or any ot er type which is driven by a motor B that is connected in circuit by a switch 0, the pump device, the same consists of a cylinder 5 in' which is a piston 6, the rod 7 of which is connected with a lever 8 that is fulcrumed at 9 on a standard 10, or any other suitable support. The lower end of the cylinder is connected with a horizontal pipe 11 which branches from the pipe 3 and is equipped with a pressure indicator 12. The lever 5 is guided by a standard 13 rising from the pipe 11, and on the lon arm of the lever are one or more adjusta le weights 14: for yieldingly opposing the pressure of the water or other fluid acting on the under side of the piston 6. It is this lever 8 which operates the switch C, but it is to be understood that any other suitable pressure responsive device may be employed for this purpose.

The switch in the present instance is shown as of the double blade type and comprises blades 15 hingedly connected to posts 16 and united by a cross bar of insulation 17, and the blades are adapted to engage spring contacts 18 which, together with the hinged posts 16, are fastened to a porcelain or other base 19. The contacts 18 are connected by wires or other connections with fused lugs 21 applied to the base 19, and these se plugs have their outer. terminals 22 connected respectively with the wires 23 and 24 of the power circuit. The switch base 19 may be fastened to a suitable panel or other support 25 that has a shelf 26 that carries the blade-operatingmechanism. The binding posts "27 and 28 are connected by the wires 29 and 30 with the terminals of the motor B for supplying current thereto. On the bracket 26 are bearings 31 in which is journaled a crank shaft 32 which has on one extremity a short crank33, and

nected by the part a screwing into the part b, so as to vary the length of the connecting rod for effecting the proper adjustment of the switch-operating means with respect to the pressure responsive device. The shaft 32 has a crank 35 which is operatively connected with-the switch blades to move the same open or closed. A link 36 is pivotally connected at 37 with the center of the bar 17 and this link has a longitudinal slot 38 into which engages a pin 39' carried on the upper part of the crank arm 35, so that a lost motion connection is provided between the crank arm 35 and link 36. On the bracket 26 are spaced abutments or stops 40 and 41 which serve to limit the movement of the crank 35, these abutments being so disposed with respect to the axis of the shaft 32 that the crank arm passes through a vertical position in moving from one extreme to the other. The crank arm has a slot 42 to accommodate a weight 43 which is suspended by a link 44 from the upper part ofthe crank arm, and the weight moves in a slot 45 provided in the bracket 26. In addition to the lost motion connection between the crank 35 and link 36 there is a lost motion connection between the connecting rod 34 and crank 33, the rod having a slot 46 in its upper end into which engages a pin 47 on the crank 33.

In describing the operation it is to be assumed that the switch is in closed position as shown in Figs. 1 and 2, so that current is supplied to the motor to operate the pump. As long as the pressure of discharge of the pump is below a certain point the motor will continue to operate, but as soon as the pressure increases the pressure responsive device B will raise the lever 8 and cause the rod 34 to travel upwardly. This brings the lower end of the slot 46 into engagement with the pin 47. The continued movement of the lever will throw the crank 35 from the position shown in Fig. 3 to that shown in Fig. 4 without however producing any effect on the blades of the switch. It will be noted that in Fig. 4 the crank 35 and the weight suspended thereby are on a dead center, and as the pressure produced by the pump increases, the crank will be thrown off its dead center and shift to the left, and in so doing, the pin 39 will strike the left end of the slot 38 of the link 36 and move the switch blades to the dotted-line position,

Fig. 3. This opening movement is effected quickly, as the weight after passing the dead center drops and causes the pin 39 to strike the end of the slot 38 with a blow which suddenly pulls the switch blades open, the crank 35 coming to rest on the stop mears 40. The motor and pump are thus stopped and the switch will be kept in open position until the pressure in the pump system falls to a predetermined point and reverses the to be understood that the slot and pin connection between the crank 33 and rod 34 permits of this sudden motion of the switch opening and closing crank 35 under the influence of the weight 43.

From the foregoing description taken in connection with the accompanying drawings, the advantages of the construction and method of operation will be readily understood by those skilled in the art to which the invention appertains, and while l have described the apparatus which I now consider to be the best embodiment thereof, I desire to have it understood that the apparatus shown is merely illustrative and that such changes may be made when desired as are within the scope of the appended claims.

Having thus described my invention, 1 claim as new and desire to secure my Letters Patent:

1. The combination of a support including a horizontal shelf, a switch mounted on the support above the shelf and including a movable contact, a crank journaled at its bottom on the shelf, a lost motion connection between the crankand movable contact for throwing the same to and from circuitclosing position, a pendulum weight carried by and suspended from the upper portion of the crank, an actuator, and a lost motion connection between the crank and actuator.

2. The combination of a support including a horizontal shelf, a switch mounted on the support above the shelf and including a movable contact, a crank journaled at its bottom on the shelf, a lost motion connection between the crank and movable contact for throwing the same to and from circuitclosing position, a pendulum weight carried by and suspended from the upper portion of the crank, an actuator, a lost motion connection between the crank and actuator, and stop devices arranged on the shelf for limiting the movement of the crank and taking the pull of the weight from the actuator.

3. The combination of a supporting structure including a shelf having an opening, a switch mounted on the support and including a swinging contact, an arm having its lower end journaled on the shelf adjacent the opening thereof, a lost motion connection between the said arm and movable contact, a weight suspended from the upper portion of the arm and extending through the opening, whereby the ends of the open= ing limit the swing of the weight, an actu- In testimony whereof I have signed my ator, a lost motion connection between the name to this specification in the presence of actuator and arm for moving the latter, and two subscribing witnesses. stops on the shelf for limiting the swing of SIDNEY S. STAHL.

5 the arm in either direction from a vertical Witnesses:

line passing through the center on which J. G. FOLEY,

- the arm swings. Enawows O. Goonwm. 

